Figure 4.

Estradiol regulation of plasma membrane ERα protein levels in ARH. A, Representative Western blot showing absence of cytosolic (C) contamination in plasma membrane (PM) preparations. Twenty micrograms of plasma membrane preparations were loaded onto a SDS-PAGE gel and probed for the cytosolic marker LIM kinase-1 (LIMK-1) or the membrane marker flotillin-1 (FLOT-1). Western blot analysis (B) and graphical representation of plasma membrane ERα (panel C) and mGluR1a (panel D) in the ARH. Plasma membrane fractions were obtained from ARH tissue, and 20 μg was loaded onto a SDS-PAGE gel and probed for ERα and mGluR1a. Levels were normalized to flotillin-1. Forty-eight hours after treatment, the 2 μg EB group up-regulated membrane ERα protein levels relative to the oil group, whereas the 50 μg EB appears to have down-regulated plasma membrane ERα protein levels relative to the 2 μg EB group by 48 hours after treatment. There was no effect of EB treatment on mGluR1a plasma membrane levels in the ARH. *, Significantly greater than oil and 50 μg EB.